[project @ 2002-05-09 13:16:29 by simonmar]

[ghc-base.git] / Data / Bits.hs

diff --git a/Data/Bits.hs b/Data/Bits.hs
index 8a37e82..52cbfb6 100644 (file)
--- a/Data/Bits.hs
+++ b/Data/Bits.hs
@@ -1,15 +1,13 @@
 {-# OPTIONS -fno-implicit-prelude #-}
 -----------------------------------------------------------------------------
--- 
+-- |
 -- Module      :  Data.Bits
 -- Copyright   :  (c) The University of Glasgow 2001
--- License     :  BSD-style (see the file libraries/core/LICENSE)
+-- License     :  BSD-style (see the file libraries/base/LICENSE)
 -- 
 -- Maintainer  :  libraries@haskell.org
 -- Stability   :  experimental
--- Portability :  non-portable
---
--- $Id: Bits.hs,v 1.1 2001/06/28 14:15:02 simonmar Exp $
+-- Portability :  portable
 --
 -- Bitwise operations.
 --
@@ -50,7 +48,7 @@ import GHC.Base
 --     Removing all fixities is a fairly safe fix; fixing the "one fixity
 --     per symbol per program" limitation in Hugs would take a lot longer.
 #ifndef __HUGS__
-infixl 8 `shift`, `rotate`
+infixl 8 `shift`, `rotate`, `shiftL`, `shiftR`, `rotateL`, `rotateR`
 infixl 7 .&.
 infixl 6 `xor`
 infixl 5 .|.
@@ -92,20 +90,13 @@ instance Bits Int where
         | i# >=# 0#            = I# (x# `iShiftL#` i#)
         | otherwise            = I# (x# `iShiftRA#` negateInt# i#)
     (I# x#) `rotate` (I# i#) =
-#if WORD_SIZE_IN_BYTES == 4
-        I# (word2Int# ((x'# `shiftL#` i'#) `or#`
-                       (x'# `shiftRL#` (32# -# i'#))))
-        where
-        x'# = int2Word# x#
-        i'# = word2Int# (int2Word# i# `and#` int2Word# 31#)
-#else
         I# (word2Int# ((x'# `shiftL#` i'#) `or#`
-                       (x'# `shiftRL#` (64# -# i'#))))
+                       (x'# `shiftRL#` (wsib -# i'#))))
         where
         x'# = int2Word# x#
-        i'# = word2Int# (int2Word# i# `and#` int2Word# 63#)
-#endif
-    bitSize  _                 = WORD_SIZE_IN_BYTES * 8
+        i'# = word2Int# (int2Word# i# `and#` int2Word# (wsib -# 1#))
+       wsib = WORD_SIZE_IN_BITS#   {- work around preprocessor problem (??) -}
+    bitSize  _                 = WORD_SIZE_IN_BITS
     isSigned _                 = True
 
 instance Bits Integer where